/*
 * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */
package java.awt;

import java.awt.peer.FileDialogPeer;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.File;
import sun.awt.AWTAccessor;

/**
 * The <code>FileDialog</code> class displays a dialog window
 * from which the user can select a file.
 * <p>
 * Since it is a modal dialog, when the application calls
 * its <code>show</code> method to display the dialog,
 * it blocks the rest of the application until the user has
 * chosen a file.
 *
 * @author Sami Shaio
 * @author Arthur van Hoff
 * @see Window#show
 * @since JDK1.0
 */
public class FileDialog extends Dialog {

  /**
   * This constant value indicates that the purpose of the file
   * dialog window is to locate a file from which to read.
   */
  public static final int LOAD = 0;

  /**
   * This constant value indicates that the purpose of the file
   * dialog window is to locate a file to which to write.
   */
  public static final int SAVE = 1;

  /*
   * There are two <code>FileDialog</code> modes: <code>LOAD</code> and
   * <code>SAVE</code>.
   * This integer will represent one or the other.
   * If the mode is not specified it will default to <code>LOAD</code>.
   *
   * @serial
   * @see getMode()
   * @see setMode()
   * @see java.awt.FileDialog#LOAD
   * @see java.awt.FileDialog#SAVE
   */
  int mode;

  /*
   * The string specifying the directory to display
   * in the file dialog.  This variable may be <code>null</code>.
   *
   * @serial
   * @see getDirectory()
   * @see setDirectory()
   */
  String dir;

  /*
   * The string specifying the initial value of the
   * filename text field in the file dialog.
   * This variable may be <code>null</code>.
   *
   * @serial
   * @see getFile()
   * @see setFile()
   */
  String file;

  /**
   * Contains the File instances for all the files that the user selects.
   *
   * @serial
   * @see #getFiles
   * @since 1.7
   */
  private File[] files;

  /**
   * Represents whether the file dialog allows the multiple file selection.
   *
   * @serial
   * @see #setMultipleMode
   * @see #isMultipleMode
   * @since 1.7
   */
  private boolean multipleMode = false;

  /*
   * The filter used as the file dialog's filename filter.
   * The file dialog will only be displaying files whose
   * names are accepted by this filter.
   * This variable may be <code>null</code>.
   *
   * @serial
   * @see #getFilenameFilter()
   * @see #setFilenameFilter()
   * @see FileNameFilter
   */
  FilenameFilter filter;

  private static final String base = "filedlg";
  private static int nameCounter = 0;

  /*
   * JDK 1.1 serialVersionUID
   */
  private static final long serialVersionUID = 5035145889651310422L;


  static {
        /* ensure that the necessary native libraries are loaded */
    Toolkit.loadLibraries();
    if (!GraphicsEnvironment.isHeadless()) {
      initIDs();
    }
  }

  static {
    AWTAccessor.setFileDialogAccessor(
        new AWTAccessor.FileDialogAccessor() {
          public void setFiles(FileDialog fileDialog, File files[]) {
            fileDialog.setFiles(files);
          }

          public void setFile(FileDialog fileDialog, String file) {
            fileDialog.file = ("".equals(file)) ? null : file;
          }

          public void setDirectory(FileDialog fileDialog, String directory) {
            fileDialog.dir = ("".equals(directory)) ? null : directory;
          }

          public boolean isMultipleMode(FileDialog fileDialog) {
            synchronized (fileDialog.getObjectLock()) {
              return fileDialog.multipleMode;
            }
          }
        });
  }

  /**
   * Initialize JNI field and method IDs for fields that may be
   * accessed from C.
   */
  private static native void initIDs();

  /**
   * Creates a file dialog for loading a file.  The title of the
   * file dialog is initially empty.  This is a convenience method for
   * <code>FileDialog(parent, "", LOAD)</code>.
   *
   * @param parent the owner of the dialog
   * @since JDK1.1
   */
  public FileDialog(Frame parent) {
    this(parent, "", LOAD);
  }

  /**
   * Creates a file dialog window with the specified title for loading
   * a file. The files shown are those in the current directory.
   * This is a convenience method for
   * <code>FileDialog(parent, title, LOAD)</code>.
   *
   * @param parent the owner of the dialog
   * @param title the title of the dialog
   */
  public FileDialog(Frame parent, String title) {
    this(parent, title, LOAD);
  }

  /**
   * Creates a file dialog window with the specified title for loading
   * or saving a file.
   * <p>
   * If the value of <code>mode</code> is <code>LOAD</code>, then the
   * file dialog is finding a file to read, and the files shown are those
   * in the current directory.   If the value of
   * <code>mode</code> is <code>SAVE</code>, the file dialog is finding
   * a place to write a file.
   *
   * @param parent the owner of the dialog
   * @param title the title of the dialog
   * @param mode the mode of the dialog; either <code>FileDialog.LOAD</code> or
   * <code>FileDialog.SAVE</code>
   * @throws IllegalArgumentException if an illegal file dialog mode is supplied
   * @see java.awt.FileDialog#LOAD
   * @see java.awt.FileDialog#SAVE
   */
  public FileDialog(Frame parent, String title, int mode) {
    super(parent, title, true);
    this.setMode(mode);
    setLayout(null);
  }

  /**
   * Creates a file dialog for loading a file.  The title of the
   * file dialog is initially empty.  This is a convenience method for
   * <code>FileDialog(parent, "", LOAD)</code>.
   *
   * @param parent the owner of the dialog
   * @throws java.lang.IllegalArgumentException if the <code>parent</code>'s
   * <code>GraphicsConfiguration</code> is not from a screen device;
   * @throws java.lang.IllegalArgumentException if <code>parent</code> is <code>null</code>; this
   * exception is always thrown when <code>GraphicsEnvironment.isHeadless</code> returns
   * <code>true</code>
   * @see java.awt.GraphicsEnvironment#isHeadless
   * @since 1.5
   */
  public FileDialog(Dialog parent) {
    this(parent, "", LOAD);
  }

  /**
   * Creates a file dialog window with the specified title for loading
   * a file. The files shown are those in the current directory.
   * This is a convenience method for
   * <code>FileDialog(parent, title, LOAD)</code>.
   *
   * @param parent the owner of the dialog
   * @param title the title of the dialog; a <code>null</code> value will be accepted without
   * causing a <code>NullPointerException</code> to be thrown
   * @throws java.lang.IllegalArgumentException if the <code>parent</code>'s
   * <code>GraphicsConfiguration</code> is not from a screen device;
   * @throws java.lang.IllegalArgumentException if <code>parent</code> is <code>null</code>; this
   * exception is always thrown when <code>GraphicsEnvironment.isHeadless</code> returns
   * <code>true</code>
   * @see java.awt.GraphicsEnvironment#isHeadless
   * @since 1.5
   */
  public FileDialog(Dialog parent, String title) {
    this(parent, title, LOAD);
  }

  /**
   * Creates a file dialog window with the specified title for loading
   * or saving a file.
   * <p>
   * If the value of <code>mode</code> is <code>LOAD</code>, then the
   * file dialog is finding a file to read, and the files shown are those
   * in the current directory.   If the value of
   * <code>mode</code> is <code>SAVE</code>, the file dialog is finding
   * a place to write a file.
   *
   * @param parent the owner of the dialog
   * @param title the title of the dialog; a <code>null</code> value will be accepted without
   * causing a <code>NullPointerException</code> to be thrown
   * @param mode the mode of the dialog; either <code>FileDialog.LOAD</code> or
   * <code>FileDialog.SAVE</code>
   * @throws java.lang.IllegalArgumentException if an illegal file dialog mode is supplied;
   * @throws java.lang.IllegalArgumentException if the <code>parent</code>'s
   * <code>GraphicsConfiguration</code> is not from a screen device;
   * @throws java.lang.IllegalArgumentException if <code>parent</code> is <code>null</code>; this
   * exception is always thrown when <code>GraphicsEnvironment.isHeadless</code> returns
   * <code>true</code>
   * @see java.awt.GraphicsEnvironment#isHeadless
   * @see java.awt.FileDialog#LOAD
   * @see java.awt.FileDialog#SAVE
   * @since 1.5
   */
  public FileDialog(Dialog parent, String title, int mode) {
    super(parent, title, true);
    this.setMode(mode);
    setLayout(null);
  }

  /**
   * Constructs a name for this component. Called by <code>getName()</code>
   * when the name is <code>null</code>.
   */
  String constructComponentName() {
    synchronized (FileDialog.class) {
      return base + nameCounter++;
    }
  }

  /**
   * Creates the file dialog's peer.  The peer allows us to change the look
   * of the file dialog without changing its functionality.
   */
  public void addNotify() {
    synchronized (getTreeLock()) {
      if (parent != null && parent.getPeer() == null) {
        parent.addNotify();
      }
      if (peer == null) {
        peer = getToolkit().createFileDialog(this);
      }
      super.addNotify();
    }
  }

  /**
   * Indicates whether this file dialog box is for loading from a file
   * or for saving to a file.
   *
   * @return the mode of this file dialog window, either <code>FileDialog.LOAD</code> or
   * <code>FileDialog.SAVE</code>
   * @see java.awt.FileDialog#LOAD
   * @see java.awt.FileDialog#SAVE
   * @see java.awt.FileDialog#setMode
   */
  public int getMode() {
    return mode;
  }

  /**
   * Sets the mode of the file dialog.  If <code>mode</code> is not
   * a legal value, an exception will be thrown and <code>mode</code>
   * will not be set.
   *
   * @param mode the mode for this file dialog, either <code>FileDialog.LOAD</code> or
   * <code>FileDialog.SAVE</code>
   * @throws IllegalArgumentException if an illegal file dialog mode is supplied
   * @see java.awt.FileDialog#LOAD
   * @see java.awt.FileDialog#SAVE
   * @see java.awt.FileDialog#getMode
   * @since JDK1.1
   */
  public void setMode(int mode) {
    switch (mode) {
      case LOAD:
      case SAVE:
        this.mode = mode;
        break;
      default:
        throw new IllegalArgumentException("illegal file dialog mode");
    }
  }

  /**
   * Gets the directory of this file dialog.
   *
   * @return the (potentially <code>null</code> or invalid) directory of this
   * <code>FileDialog</code>
   * @see java.awt.FileDialog#setDirectory
   */
  public String getDirectory() {
    return dir;
  }

  /**
   * Sets the directory of this file dialog window to be the
   * specified directory. Specifying a <code>null</code> or an
   * invalid directory implies an implementation-defined default.
   * This default will not be realized, however, until the user
   * has selected a file. Until this point, <code>getDirectory()</code>
   * will return the value passed into this method.
   * <p>
   * Specifying "" as the directory is exactly equivalent to
   * specifying <code>null</code> as the directory.
   *
   * @param dir the specified directory
   * @see java.awt.FileDialog#getDirectory
   */
  public void setDirectory(String dir) {
    this.dir = (dir != null && dir.equals("")) ? null : dir;
    FileDialogPeer peer = (FileDialogPeer) this.peer;
    if (peer != null) {
      peer.setDirectory(this.dir);
    }
  }

  /**
   * Gets the selected file of this file dialog.  If the user
   * selected <code>CANCEL</code>, the returned file is <code>null</code>.
   *
   * @return the currently selected file of this file dialog window, or <code>null</code> if none is
   * selected
   * @see java.awt.FileDialog#setFile
   */
  public String getFile() {
    return file;
  }

  /**
   * Returns files that the user selects.
   * <p>
   * If the user cancels the file dialog,
   * then the method returns an empty array.
   *
   * @return files that the user selects or an empty array if the user cancels the file dialog.
   * @see #setFile(String)
   * @see #getFile
   * @since 1.7
   */
  public File[] getFiles() {
    synchronized (getObjectLock()) {
      if (files != null) {
        return files.clone();
      } else {
        return new File[0];
      }
    }
  }

  /**
   * Stores the names of all the files that the user selects.
   *
   * Note that the method is private and it's intended to be used
   * by the peers through the AWTAccessor API.
   *
   * @param files the array that contains the short names of all the files that the user selects.
   * @see #getFiles
   * @since 1.7
   */
  private void setFiles(File files[]) {
    synchronized (getObjectLock()) {
      this.files = files;
    }
  }

  /**
   * Sets the selected file for this file dialog window to be the
   * specified file. This file becomes the default file if it is set
   * before the file dialog window is first shown.
   * <p>
   * When the dialog is shown, the specified file is selected. The kind of
   * selection depends on the file existence, the dialog type, and the native
   * platform. E.g., the file could be highlighted in the file list, or a
   * file name editbox could be populated with the file name.
   * <p>
   * This method accepts either a full file path, or a file name with an
   * extension if used together with the {@code setDirectory} method.
   * <p>
   * Specifying "" as the file is exactly equivalent to specifying
   * {@code null} as the file.
   *
   * @param file the file being set
   * @see #getFile
   * @see #getFiles
   */
  public void setFile(String file) {
    this.file = (file != null && file.equals("")) ? null : file;
    FileDialogPeer peer = (FileDialogPeer) this.peer;
    if (peer != null) {
      peer.setFile(this.file);
    }
  }

  /**
   * Enables or disables multiple file selection for the file dialog.
   *
   * @param enable if {@code true}, multiple file selection is enabled; {@code false} - disabled.
   * @see #isMultipleMode
   * @since 1.7
   */
  public void setMultipleMode(boolean enable) {
    synchronized (getObjectLock()) {
      this.multipleMode = enable;
    }
  }

  /**
   * Returns whether the file dialog allows the multiple file selection.
   *
   * @return {@code true} if the file dialog allows the multiple file selection; {@code false}
   * otherwise.
   * @see #setMultipleMode
   * @since 1.7
   */
  public boolean isMultipleMode() {
    synchronized (getObjectLock()) {
      return multipleMode;
    }
  }

  /**
   * Determines this file dialog's filename filter. A filename filter
   * allows the user to specify which files appear in the file dialog
   * window.  Filename filters do not function in Sun's reference
   * implementation for Microsoft Windows.
   *
   * @return this file dialog's filename filter
   * @see java.io.FilenameFilter
   * @see java.awt.FileDialog#setFilenameFilter
   */
  public FilenameFilter getFilenameFilter() {
    return filter;
  }

  /**
   * Sets the filename filter for this file dialog window to the
   * specified filter.
   * Filename filters do not function in Sun's reference
   * implementation for Microsoft Windows.
   *
   * @param filter the specified filter
   * @see java.io.FilenameFilter
   * @see java.awt.FileDialog#getFilenameFilter
   */
  public synchronized void setFilenameFilter(FilenameFilter filter) {
    this.filter = filter;
    FileDialogPeer peer = (FileDialogPeer) this.peer;
    if (peer != null) {
      peer.setFilenameFilter(filter);
    }
  }

  /**
   * Reads the <code>ObjectInputStream</code> and performs
   * a backwards compatibility check by converting
   * either a <code>dir</code> or a <code>file</code>
   * equal to an empty string to <code>null</code>.
   *
   * @param s the <code>ObjectInputStream</code> to read
   */
  private void readObject(ObjectInputStream s)
      throws ClassNotFoundException, IOException {
    s.defaultReadObject();

    // 1.1 Compatibility: "" is not converted to null in 1.1
    if (dir != null && dir.equals("")) {
      dir = null;
    }
    if (file != null && file.equals("")) {
      file = null;
    }
  }

  /**
   * Returns a string representing the state of this <code>FileDialog</code>
   * window. This method is intended to be used only for debugging purposes,
   * and the content and format of the returned string may vary between
   * implementations. The returned string may be empty but may not be
   * <code>null</code>.
   *
   * @return the parameter string of this file dialog window
   */
  protected String paramString() {
    String str = super.paramString();
    str += ",dir= " + dir;
    str += ",file= " + file;
    return str + ((mode == LOAD) ? ",load" : ",save");
  }

  boolean postsOldMouseEvents() {
    return false;
  }
}
